392
FXUS61 KCTP 061132
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
732 AM EDT Sun Apr 6 2025

.SYNOPSIS...
* Several frontal boundaries moving slowly SE across the
  Commonwealth will bring periods of rain over much of the
  region and a chance of a few thunderstorms across Southern PA
  into the mid morning hours today.
* An unsettled pattern continues into early in the upcoming week
  with periods of rain showers, mixing with or changing to snow
  showers across northern Pennsylvania.
* High pressure will bring drier conditions on Wednesday before
  showers return on Thursday and into the end of the week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A triple point about 30 NM NW of KIPT at 05Z Sunday has a narrow
wedge of slightly warmer, higher Theta-E air along the I-99 and
RT 219 corridors to the south of Interstate 80. A compact jet
max will slide across the Upper Ohio River Valley and near the
Mason-Dixon line this morning. This feature and its associated
diff PVA will combine with the approaching Cfront and uvvel over
the quasi-stnry boundary/cool air damming across the eastern
half of PA to create periods of light to moderate rain through
about 12-14Z today. The bulk of the rain will occur over the SE
half of the CWA where an additional 0.25 to 0.50 of an inch of
rain is expected.

the leading edge of SFC ridging and the bulk of the rain will
shift to the southern tier counties of PA by the late morning
and into the Virginias this afternoon as drier air advects south
across the region at the lowest levels. Southwesterly flow above
this initially very shallow colder air mass will keep plenty of
thick clouds across the entire region today with bases not
likely rising above 5 or 6 KFT AGL anywhere (and lower CIGS
hanging tough over the southern tier and NRN/WRN Mtns of the
state.

Lingering showers along with some areas of drizzle and fog on
the ridges will occur across Southern PA through dusk today.

Min temps this morning will range from the mid 30s across the
Far NW to the low-mid 50s across the southern Valleys.

High temps today will display a fairly large, 20 to 25 deg F
range from NW to SE across the CWA , with maxes between 35-40 F
near and to the west of KBFD and in the mid to upper 50s across
Far southern York and Lancaster Counties.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
As the colder air gradually deepens later today and tonight
(with the Dendritic Growth Zone dipping into the upper quarter
of the cloud layer over the high terrain of the North and West),
showers will mix with or even change to wet snow across the
Northern Mtns, and to a lesser deg over the Laurel Highlands.

A relatively weak wave of low pressure will move northeast
along this nearly stalled out frontal boundary later tonight
and early Monday, bringing a 6 to 10 hour period of rain in
the south and mixed rain and wet snow across portions of the
Central Mountains and Middle Susquehanna Region.

Mixed precipitation or wet snow will likely overspread the
region from the Southwest this evening and continue overnight as
snow over the Mtns of Northern PA. Up to 2 inches of
accumulation is possible across the higher terrain of Northern
PA (with the target area appearing to be near and up to 25 NM
north of I-80 in NCentral PA), mainly at elevations over 1500
feet above sea level.

Drier air working into Central PA on Monday behind departing
low pressure will bring an end to any lingering rain or snow
showers, though skies will remain mostly cloudy.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
All guidance shows a shortwave tracking north of Pennsylvania
Monday night, bringing another cold front through the area.

Some snow showers will be possible along the front, though with
the best moisture and forcing passing north of the New York
border, the best chance of any light snow will be over the
northwest mountains.

Much colder air works in behind the cold front, with ensemble
mean 850 temps of -8 to -12 C supporting high temperatures on
Tuesday in the 30s and 40s (which will likely be the coldest
daytime air felt until the Autumn across the region).

This airmass will also be cold enough to allow for at least a
few lake effect and upslope snow showers through early Tuesday
afternoon before subsidence increases as high pressure builds
in. Snowfall amounts will generally be less than an inch. Gusty
winds during the day on Tuesday will make it feel very chilly
with apparent temperatures in the teens and low 20s across the
northern and western mountains.

High pressure will keep dry and cool conditions in place
through Wednesday, but temperatures will begin to moderate
towards the end of the week. With temperatures expected to be
below freezing Monday, Tuesday, and Wednesday nights for most of
the area, make sure to take any necessary precautions to protect
any sensitive vegetation that may be growing already. Most
guidance shows another system moving in for Thursday/Friday but
there is still a lot of uncertainty in the timing and precip
amounts.

Mean long wave trough over the eastern US with several embedded
short waves will bring a few more bouts of rain/showers late
this upcoming week and early next weekend. The precip could be
mixed or fall as some wet snow at times across the higher
terrain of the north and west, considering 850 mb temps
hovering in the 0 to -3C range, plenty of cloud cover and a
predominant NE to northerly LLVL flow of cold air at the
surface.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Fog and low ceilings continue across much of central PA on both
sides of a cold front, with IFR to LIFR conditions. Conditions
will likely improve from UNV south and eastward as winds shift
around to the NW promoting downsloping in this region. By
10-13z, AOO, UNV and IPT will likely be the first to improve to
MVFR. Meanwhile, MDT and LNS will likely see cigs and vsby
lower first before improving later, trending toward MVFR by
12-15z as the NW flow arrives. As drier air works in later in
the afternoon from the NW, VFR conds are expected at all sites
except JST, where MVFR cigs will linger the longest. NW winds
will gust 15-20 kts through the first half of the day,
decreasing during the afternoon.

A wave riding along the thermal boundary to our south and east
Sunday night will bring lower cigs and an increasing chance for
precip, with light, wet snow possible from UNV north and west.

Outlook...

Mon-Tue...Restrictions likely NW Mtns. Snow showers possible.

Wed...No sig wx/VFR conditions expected.

Thu...Rain enters W, overspreads E. Restrictions possible.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SYNOPSIS...Lambert/NPB
NEAR TERM...Lambert
SHORT TERM...Lambert
LONG TERM...Lambert/Bauco
AVIATION...Colbert/NPB